num keys 1 , 2 , 3 , 0 , . , enter and right arrow key is not working is there a way to fix it?

First, are all other keys working okay? If they are, then part of the circuit board beneath the keys you've mentioned may have cracked. I doubt that it can be repaired, and replacement keyboards are not expensive.

Assuming you're using OS X, you don't have to buy an Apple keyboard. PC k/b's work perfectly well with Mac - and they're a darn sight cheaper! There are several posts on the topic of using PC peripherals on Mac computers.